Collaborative care for depression and anxiety problems

This review is published as a Cochrane Review in the Cochrane Database of Systematic Reviews 2012, Issue 10. Cochrane Reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and the Cochrane Database of Systematic Reviews should be consulted for the most recent version of the Review.Common mental health problems, such as depression and anxiety, are estimated to affect up to 15% of the UK population at any one time, and health care systems worldwide need to implement interventions to reduce the impact and burden of these conditions. Collaborative care is a complex intervention based on chronic disease management models that may be effective in the management of these common mental health problems

Reassessment of biogenic volatile organic compound emissions in the Atlanta area

Localized estimates of biogenic volatile organic compound (BVOC) emissions are important inputs for photochemical oxidant simulation models. Since forest tree species are the primary emitters of BVOCs, it is important to develop reliable estimates of their areal coverage and BVOC emission rates. A new system is used to estimate these emissions in the Atlanta area for specific tree genera at hourly and county levels. The U.S. Department of Agriculture, Forest Service Forest Inventory and Analysis data and an associated urban vegetation survey are used to estimate canopy occupancy by genus in the Atlanta area. A simple canopy model is used to adjust photosynthetically active solar radiation at five vertical levels in the canopy. Lraf temperature and photosynthetically active radiation derived from ambient conditions above the forest canopy are then used to drive empirical equations to estimate genus level emission rates of BVOCs vertically through forest canopies. These genera-level estimates are then aggregated to county and regional levels for input into air quality models and for comparison with (1) the regulatory model currently used and (2) previous estimates for the Atlanta area by local researchers. Estimated hourly emissions from the three approaches during a documented ozone event day are compared. The proposed model yields peak diurnal isoprene emission rates that are over a factor of three times higher than previous estimates. This results in total BVOC emission rates that are roughly a factor of two times higher than previous estimates. These emissions are compared with observed emissions from forests of similar composition. Possible implications for oxidant events are discussed. © 1995

An improved model for estimating emissions of volatile organic compounds from forests in the eastern United States

The US Department of Agriculture, Forest Service Forest Inventory and Analysis Eastwide Database is used to describe the areal extent, species composition, and tree diameter distributions of United States forests. Horizontal canopy occupancy by genera is then estimated as a function of diameter at breast height. Growing season peak foliar masses are derived from the empirical literature for canopies of deciduous and coniferous genera. A simple canopy model is used to adjust photosynthetically active solar radiation at five vertical levels in the canopy. Leaf temperature and photosynthetically active radiation derived from ambient conditions above the forest canopy are then used to drive empirical equations to estimate genus level emission rates of BVOCs vertically through forest canopies. -Author

Active turbulence and scalar transport near the forest-atmosphere interface

Turbulent velocity, temperature, water vapor concentration, and other scalars were measured at the canopyatmosphere interface of a 13-14-m-tall uniform pine forest and a 33-m-tall nounuiform hardwood forest. These measurement were used to investigate whether the mixing layer (ML) analogy of Raupach et al. predicts eddy sizes and now characteristics responsible for much of the turbulent stresses and vertical scalar fluxes. For this purpose, wavelet spectra and cospectra were derived and analyzed. It was found that the MI. analogy predicts well vertical velocity variances and integral timescales. However, at low wavenumbers, inactive eddy motion signatures were present in horizontol velocity wavelet spectra, suggesting that MI. may not be suitable for scaling horizontal velocity perturbations. Momentum and scalar wavelet cospectra of turbulent stresses and scalar fluxes demonstrated that active eddy motion, which was shown by Raupach et al. to be the main energy contributor to vertical velocity (w) spectral energy (Em). is also the main scalar flux-transporting eddy motion. Predictions using ML of the peak E, frequency are in excellent agreement with measured waveled cospectral peaks of vertical fluxes (Kh = 1.5, where K is wavenumber and h is canopy height). Using Lorentz wavelet thresholding of vertical velocity time series, wavelet coefficients associated with active turbulence were identified. It was demonstrated that detection frequency of organized structures, as predicted from Lorentz wavelet filtering, relate to the arrival frequency /h and integral timescale, where is the mean horizontal velocity at height z = h. The newly proposed wavelet thresholding approach, which relies on a"global" wavelet threshold formulation for the energy in w, provides simultaneous energy-covariance-preserving characterization of "active" turbulence at the canopy-atmosphere interface

Biogenic isoprene emission: Model evaluation in a southeastern United States bottomland deciduous forest

Isoprene is usually the dominant natural volatile organic compound emission from forest ecosystems, especially those with a major broadleaf deciduous component. Here we report isoprene emission model performance versus leaf and canopy level isoprene emission measurements made at the Duke University Research Forest near Chapel Hill, North Carolina. Emission factors, light and temperature response, canopy environment models, foliar mass, leaf area, and canopy level isoprene emission were evaluated in the field and compared with model estimates. Model components performed reasonably well and generally yielded estimates within 20% of values measured at the site. However, measured emission factors were much higher in early summer following an unusually dry spring. These decreased later in the summer but remained higher than values currently used in emission models. There was also a pronounced decline in basal emission rates in lower portions of the canopy which could not be entirely explained by decreasing specific leaf weight. Foliar biomass estimates by genera using basal area ratios adjusted for crown form were in excellent agreement with values measured by litterfall. Overall, the stand level isoprene emissions determined by relaxed eddy accumulation techniques agreed reasonably well with those predicted by the model, although there is some evidence for underprediction at ambient temperatures approaching 30°C, and overprediction during October as the canopy foliage senesced. A "Big Leaf" model considers the canopy as a single multispecies layer and expresses isoprene emission as a function of leaf area rather than mass. This simple model performs nearly as well as the other biomass-based models. We speculate that seasonal water balance may impact isoprene emission. Possible improvements to the canopy environment model and other components are discussed

Performance test of a sorbent tube sampler with respect to analyte loss in collecting biogenic volatile organic compounds

The superiority of thermal desorption-gas chromatography (TD-GC) applications is well known for the analysis of biogenic volatile organic compounds (BVOC). Despite the recognition of potential biases associated with sorptive loss reaction, the interaction of reactive BVOC with a sorbent tube (ST) sampler has not been sufficiently investigated. In this study, the extent of such a loss on a sampling device was studied against the sorbent holder materials by comparing stainless steel (SS; main target) and quartz (QZ; reference). To this end, three bed STs (Tenax TA, Carbopack B, and Carbopack X) were prepared using both holding materials (SS vs. QZ). The extent of BVOC loss was then tested for each material against two different phases (liquid and vapor) of ten monoterpenes. Accordingly, the soptive loss on the SS holder ranged from 10 % (vapor) to 20 % (liquid). If a vapor phase BVOC was forced to pass through an empty SS tube, the extent of their loss increased further in a range of 21.1 % (β-P) to 43.5 % (α-T). Likewise, similar loss rates (about 10 % reductions) were also observed when analyzing some environmental samples (pine needle) from the SS holder relative to QZ. Thus, a QZ tube is recommended over a SS tube to avoid sample loss in the collection of BVOC.This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (grant number 2013004624). We also acknowledges the support of “Cooperative Research Program for Agriculture Science & Technology Development (Project title: Study on model development to control odor from Pigpen Project No. PJ01052101)” Rural Development Administration, Republic of Korea